Various carboxylic acids and derivatives thereof have been reduced to alcohols. U.S. Pat. No. 4,073,813, Cordier, is illustrative of references which teach catalytic hydrogenation of ethylenically unsaturated aldehydes to alcohols, including dienyl alcohols.
Carboxylic acid and derivatives thereof have also been reduced to alcohols with metal hydrides. It has been reported, for example, that 2,4-hexadienal has been reduced to 2,4 hexadien-1-ol (sorbyl alcohol) with sodium borohydride.
G. F. Woods et al., J. Am. Chem. Soc. volume 77, 1800 (1955), disclose lithium aluminum hydride reduction of 2,4-hexadienal to sorbyl alcohol.
R. F. Nystrom and W. G. Brown, J. Am. Chem. Soc., volume 69, 2548 (1947) describe reduction of several carboxylic acids, including sorbic acid and cinnamic acid, to alcohols using lithium aluminum hydride. The authors report that the olefinic double bonds of sorbic acid are not reduced whereas the double bond of cinnamic acid is.
R. F. Nystrom and W. G. Brown, J. Amer. Chem. Soc., volume 69, 1197 (1947) describe reduction of aldehydes, ketones, carboxylate esters, acid chlorides and acid anhydrides using lithium aluminum hydride. The esters are aromatic, mono-unsaturated or saturated. Sorboyl chloride is reduced to sorbyl alcohol.
R. F. Nystrom et al., J. Am. Chem. Soc., volume 71, 3245 (1949) describe reduction of certain aromatic or saturated aldehydes, ketones, carboxylate esters and carboxylic acids using lithium borohydride as the reducing agent.
M. S. Brown and H. Rapaport, J. Org. Chem., volume 28, 3261 (1963) describe reduction of methyl esters of various carboxylic acids to alcohols using a large excess of sodium borohydride in methanol. Some of the carboxylates are mono-unsaturated, in which cases the authors note reduction of the double bonds.
S. W. Chaikin and W. G. Brown, J. Am. Chem. Soc., volume 71, 122 (1949) disclose reduction of various aldehydes, ketones and acid chlorides using sodium borohydride. The authors report that olefinic double bonds of mono-unsaturated aldehydes and ketones were not reduced but that those of crotonyl chloride and cinnamoyl chloride were reduced.
J. Nikawa and T. Shiba, Chem. Letters, 981 (1979) describe reduction of 1-succinimidyl esters of various saturated carboxylic acids using sodium borohydride in tetrahydrofuran.
B. C. Subba Rao, Current Science, number 6, 218 (1961), report reduction of various methyl carboxylates, including crotonic acid, using a sodium borohydride-titanium (IV) chloride reagent. Reduction of crotonic, oleic and cinnamic acids, as free acids, resulted in saturated alcohols.
T. Koizumi et al., Chem. Pharm. Bull. (Japan), volume 21, number 2, 312 (1973) describe preparation of mixed carboxylic-diphenylphosphoric anhydrides by reacting carboxylic acids with diphenylphosphorochloridate in the presence of triethylamine in tetrahydrofuran, and reduction of the resulting mixed anhydrides using sodium borohydride. Cinnamic acid is the only unsaturated and nonaromatic acid reported.
K. Ishizumi et al., Chem. Pharm. Bull. (Japan), volume 16, number 3, 492 (1968) describe in situ preparation of acid anhydrides of several carboxylic acids and reduction of the anhydrides with sodium borohydride in aqueous tetrahydrofuran. Cinnamic acid is the only unsaturated and nonaromatic acid reported. The anhydrides were prepared by reacting the acids with ethyl chloroformate and triethylamine in tetrahydrofuran.
To date, there has not been a convenient, inexpensive process for preparing conjugated dienyl alcohols, herein referred to as conjugated dienols. There has not been a process for preparing conjugated dienols from activated acid esters. D. S. Tarbell and N. A. Leister, J. Org. Chem., volume 23, 1149 (1958) disclose mixed anhydrides prepared by reacting sorbic acid with ethyl chloroformate in the presence of triethylamine.
L. E. Overman et al., J. Org. Chem., volume 43, 2164 (1978), describe preparation of 1-N-acylamino-1,3-dienes from 2,4-pentadienoic acid or sorbic acid. The preparation proceeds through mixed anhydrides prepared by reacting the free acid with ethyl chloroformate in the presence of diisopropylethylamine or triethylamine; irreproducible results were obtained using the pentadienoic acid in the presence of triethylamine.
Fernholz et al., U.S. Pat. No. 3,468,948, disclose preparation of a sorbic acid anhydride by reacting the polyester of 3-hydroxy-4-hexenoic acid with a chloroformate in the presence of triethylamine.
Andrews, U.S. Pat. No. 4,293,674 discloses compounds prepared by transesterification of conjugated dienols and alkyl methacrylates, as well as homopolymers and copolymers of such compounds. Milligan et al., U.S. Pat. No. 3,520,839, disclose other uses for compounds derived from sorbyl alcohol including, for example, carbamate insecticides.
G. W. Anderson et al., J. Am. Chem. Soc., volume 86, 1839 (1964) report that N-hydroxysuccinimidyl esters of amino acids are more active towards peptidization. The -imide esters are prepared by reacting the free acid with N-hydroxysuccinimide in the presence of dicyclohexylcarbodiimide in tetrahydrofuran.